PILOTFARMS
Actual Plant Nutrient Results All pilot farms carry out detailed plant nutrient calculations - both for the whole farm and for each production area. Plant nutrient calculations have been carried out over several years allowing the possibility for showing differences between farms as well as results achieved. By way of introduction, it must be pointed out that crop cultivation, and therefore plant nutrient utilisation, are by and large influenced by climate and yearly variations. A specific year can give poor yield and therefore an inferior result even if the ambition was to improve plant nutrient utilisation. This project documents actual results, first and foremost on the basis of years 1996 and 1997. |
| Figure 1 - Flow of Plant nutrients for the whole farm and each
production area. A very considerable amount of the farms plant nutrient supply flows as input over the "farm boundary". In the case of farms with principally crop cultivation, in the form of mineral fertiliser, but for farms with animal production, a large proportion of plant nutrient flows into the farm in the form of purchased fodder. On several farms with animal husbandry, input via fodder is as large as input via mineral fertiliser. A pool of plant nutrients is continually build up on farms with intensive animal husbandry. Output via milk and meat is often low in proportion to input. At the same time, crops converted to animal products are also a part of the system. The pilot farms carry out a detailed account of the flow to animal production as well as that which is returned to crop production in the form of animal manure. Nutrient losses occurring in the stables and in storage are debited as losses from animal production. Losses in connection with the spreading of manure are debited from crop production. An important part of nutrient flow concerns build-up as well as "exploitation" of the soils own reserve of plant nutrients. At present this part is not accounted for in plant nutrient balances. Emphasis has been placed on building up a model which can account for practical conditions on the farm. |
| Figure 2 - Plant nutrient utilisation for farms with different
productions aims. Reported results form an average for two farms within respective production areas. Farms with only crop production achieve, as a rule, good utilisation. It is easier to adjust plant nutrient input when crop production is managed without the use of organic manure. At the same time it is necessary achieve a better utilisation of existing stable manure as well as, in the future, nutrients contained in remainder products as off farm sludge and compost. The use of remainder products must not lead to a damaging input from heavy metals or inorganic pollutants. Pasture - dairy farms have a lower utilisation which is hard to avoid when plant material is converted / processed into valuable milk |
| Figure 3 - Nitrogen utilisation for crop production farms with
different aims. Crop production farms with predominant cereal production show as a rule a high plant nutrient utilisation. Output of seed is relatively large in proportion to supply of plant nutrients. For example, pasture seed, oil-plant and many types of vegetables demand large inputs of nutrients in order to achieve a high yielding crop with good quality. Cereal crops are relatively certain entailing that yields are, as a rule, of a level which can be used as a basis for determining fertiliser needs. For certain years can heavy rain, hail and frost give unforeseen yield reductions. A yield reduction in connection with anticipate yield can lead to worsened plant nutrient utilisation. |
| Figure 4 - Nitrogen utilisation for different crops. Winter wheat and sugar-beet have, as rule, given best nitrogen utilisation. Leguminous plants have a very good "utilisation" in regard to the crop being supported with nitrogen fixation. Plant nutrient utilisation is greatly improved when straw is used as fodder or as a source of energy. Removal of straw for bio-energy must not lead to a lowering of soil humus content, an important factor in maintaining soil fertility. Sugar-beet has the capacity to utilise a large percentage of the growing season giving conditions for high yield - in return a large removal which leads to good utilisation. Nutrients taken up in the tops of the sugar-beet are accounted for only in the case when the tops harvested and leave the field for example as fodder. Their is no yield of tops in figure 4. Oil-plants, many table vegetables and grass for pasture seed are crops that demand large inputs of plant nutrients but where nutrient removal is low as a result of a low biological yield. Nitrogen utilisation is, as rule, low for these crops. |
| Figure 5 - Example of improved plant nutrient utilisation. Plant
nutrient utilisation on a farm with crop production and fattening pigs 1994-97. Plant nutrient utilisation has on this farm increased during 96 and 97. The farms liquid manure was previously spread during Autumn before ploughing and sowing of winter cereals. During recent years all manure has been spread during spring in growing crops. This has led to a much improved utilisation of nutrients from the farms manure - a resource on the farm. As a result it has been possible to reduce the use of mineral fertiliser. The total input of plant nutrients from outside the farm has been reduced while at the same time the output of animal products and crops are at the same level. The result is improved nutrient utilisation. An exceptional example of controlling plant nutrient input. |
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Last changed: april 17, 2007
